the brother on the run, dzhokhar tsarnaev, age 19. >> in my fbi days, we had a term for tier one terrorists, the most dangerous terrorists. we used to call them bomb chuckers. we have a real life bomb chucker on the loose. >> reporter: in and around boston, everyday life ground to a halt. police departments made emergency calls to residents. >> stay indoors until further instructions. >> reporter: just after 10:00 a.m. this is what watertown, massachusetts neighborhoods looked like. police on the street, helicopters overhead, nearly a million people in six different communities have been simply told to stay indoors after an anxiety-filled week, it's a day like nothing boston has ever experienced. nbc news correspondent kerry sanders was on the "today" show from watertown when police told him to take cover. >> the officer started to yell get down, get down. >> reporter: the uncle of the surviving brother pleaded with his nephew. >> i say if you are alive turn yourself in and ask for forgiveness for the victims and the injured. >> reporter: as dusk was falling tonight, another break in the ma